572 METASPERMAE OF THE MINNESOTA VALLEY. 



area of drainage, then, the valley of the Minnesota is one of 

 central location. Its continental position is no less central. If 

 the 50th meridian west of Greenwich be taken for the eastern 

 boundary of the solid portion of the North American continent 

 and the 140th meridian, passing near Mount St. Elias and cut- 

 ting off the great Alaskan peninsula, for the western, the inter- 

 mediate meridian will be the 95th west of Greenwich, and this 

 meridian passes squarely through the valley of the Minnesota, 

 cutting the counties of Jackson, Cottonwood, Brown, Redwood, 

 Renville and Kandiyohi. Or if the meridian of 20° west be 

 be taken for the eastern boundary of the North American con- 

 tinent, thus includmg the whole of Greenland, and the merid- 

 ian of 170° west be taken for the western boundary, thus in- 

 cluding the Alaskan peninsula and passing through Berings 

 straits, the intermediate meridian as before is the 95th west. 

 In like manner, if the parallel of 70° north latitude, passing 

 near the mouth of the Mackenzie river, and the parallel of 20° 

 north latitude passing near the city of Mexico be adopted as 

 the northern and southern boundaries, respectively, of the 

 solid portion of the North American continent, the intermedi- 

 ate parallel will be the 45th of north latitude and this passes 

 through Hennepin, Kandiyohi, Chippewa and Lac Qui Parle 

 counties of the valley in Minnesota, and through Grant and 

 Codington counties in South Dakota. The same 45th parallel 

 becomes the intermediate one if 80° north latitude be selected 

 for the northern boundary and 10° north latitude for the south- 

 ern. The 95th meridian and the i5th parallel intersect in Kan- 

 diyohi county just at the north edge of the valley. 



The continental and hydrographic position of the Minnesota 

 basin is seen to be peculiarly central and this adds much to the 

 interest of determining the character of its plant inhabitants. 



General topDgraphical features. Big Stone lake which is 

 the head lake of the main stream lies at an altitude of 962 feet 

 above the sea. Into the northwestern part of this lake, near 

 the town of Brown's Valley, the head stream enters after 

 running for about twenty-two miles in a southeastern direction 

 from the Coteau des Prairies of South Dakota. This head 

 stream drains land that lies at aa elevation of 2,000 feet above 

 the sea level. The two principal tributaries from the north 

 are the Pomme de Terre and the Chippewa rivers, both of 

 which arise in the high morainic hills of southern Otter Tail 

 county. Some of these hills reach an altitude of 1,750 feet 

 above the level of the sea. Lake Stalker which is the head 



